The four research projects in this P01 application on obesity and cancer will all use imaging-derived measures of body fat compartments as their exposures of interest. Imaging data at the two study sites [University of Hawaii (UH) and University of California (USC)] will be acquired by whole-body Dual X-ray Absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI). Since data acquisition and analysis of imaging measures in a multi-center setting require specialized techniques and knowledge, we propose the creation of a dedicated Body Fat Compartments Imaging Core. The Core's main role will be the quantitative assessment of body fat distribution in 2,000 Multiethnic Cohort participants [800 at USC, 1,200 at the UH]. The Core will be co-directed by Dr. Thomas Ernst, an MR Physicist at the UH Medical School, and Dr. John Shepherd, Associate Professor of Radiology at UCSF. Both are experts in performing and analyzing DXA scans in a multi-center setting. The Core will provide the following services to the projects: Development, implementation and maintenance of optimized and uniform scanning protocols and quality assurance (QA) procedures for the two MEC study sites Data acquisition, archival, distribution, and processing Weekly quality assurance scans and monitoring Ongoing evaluation of technical quality using in vivo data from individual subjects Installation and maintenance of customized post-processing packages The Body Fat Compartments Imaging Core will certify sites and scanners before human studies may be started, perform continuous quality assurance, resolve potential technical issues in a timely manner, and provide intellectual input into the scientific findings of the study. Thus, having a dedicated Body Fat Compartments Imaging Core will ensure that consistent, high-quality imaging data are collected across sites and over time in a cost-effective manner.